Experimental investigation of standard effective temperature (SET*) adapted for human walking in an indoor and transitional thermal environment.

Thermal indices are widely used to predict the human body's thermal sensation indoors and outdoors, with standard effective temperature (SET*) being the most commonly used index. Although SET* has been well-proven in predicting indoor static thermal comfort, it has not yet proven its applicability in thermal comfort and dynamic condition assessments outdoors. Refers to verify the application of SET* in both an indoor and transitional space, experiments were conducted in the badminton hall of Guangzhou University (representing the indoor space) and the overhead floor of the experimental building of Guangzhou University (representing the transition space). Thirty healthy college students were first asked to walk for 20 min at four walking speeds and then to rest for 10 min. During the whole process, environmental parameters and the mean thermal sensation vote (MTSV) were recorded. Thereafter, the relationship between MTSV and the calculated SET* was established; notably, the applicability of the SET* prediction model in the transitional space was significantly better than that in the indoor space during walking. An improved SET* prediction model and the corresponding thermal stress categories are proposed to predict the dynamic thermal sensation, which is suitable for either walking indoors or in transitional spaces. From the linear regression equation in the improved model, it was obtained that the thermal comfort interval (MTSV falling within ±0.5) represented by α SET* is 24-37.5 °C. In addition, through Probit regression analysis, the thermal sensation level corresponding to the improved SET* (α SET*) was determined.